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The team identified an unresolved issue (U … The team identified an unresolved issue (URI) related to the licensee s failure to use worst case voltage for motor starting calculations. Specifically, the licensee assumed voltage near to the administratively controlled minimum offsite voltage rather than the voltage afforded by the setpoint of the DV relay defined in the TS.The original NRC Safety Evaluation Report, NUREG-0519, dated March 1981 - Section 8.2.2.2, Low And/Or Degraded Grid Voltage Condition required the implementation of a second level undervoltage scheme to protect safety-related loads and stated, in part, the voltage and time setpoints will be determined from analysis of voltage requirements of the safety-related loads. Updated Final Safety Analysis Report 8.2.3.2.2, Criteria for Acceptable Voltage states in part, The minimum acceptable level (i.e., starting voltage) for safety-related motors is based on the minimum equipment terminal voltages postulated at the lower analytical limit or design basis of the second-level undervoltage protection setpoint. LaSalle TS Table 3.3.8.1 specified the Allowable Value for the degraded-voltage relay voltage setpoint as Y3814V and U3900V. Calculation AN71 also defined the Analytical Limit for the degraded voltage relay as 3814V (approximately 91.7 percent of 4160V).The team determined that Calculation L-003364 only analyzed steady state motor running and individual motor starting with 3814V on the safety bus. The calculation did not consider or analyze block loading at the worst case voltage allowed by the Technical Specification setpoint without disconnecting from offsite power. The team calculated the lowest value the relay will reset is at 3833V. This value reflects the vendor\\\'s specified dropout to reset ratio for the relay of 99.5 percent and the Technical Specification setpoint of 3814V (3814/0.995=3833). Therefore, based on a Technical Specification analytical limit of 3814V, a reset ratio of 99.5 percent, and block loading conditions, the lowest voltage that can occur on the bus immediately following block loading, without separating from the grid will be 3833V.The team noted that Calculation L-003364 analyzed motor starting voltage during block loading using a switchyard voltage input of 352kV, which was intended to bound the minimum expected switchyard voltage of 354kV, defined in UFSAR 8.2.3.2, Adequacy of Offsite Power. This resulted in safety bus voltage of approximately 3960V vs. the analytical limit of 3814V. The team determined that the corresponding switchyard voltage for a fully loaded safety bus at 3833V is 341.5kV, which is considerably below the value used by the licensee in their calculation of 352kV. Since licensee s approach was not consistent with UFSAR 8.2.3.2.2 which states that motor starting voltage was based on lower analytical limit or design basis of the second level undervoltage protection setpoint, the team concluded that the block motor starting results in Calculation L-003364 were non conservative by approximately 3 percent. In response to the teams concerns, the licensee stated that the LaSalle licensing basis did not require postulating a concurrent LOCA and degraded voltage condition. After consultation with NRR and review of the LaSalle licensing record, including FSAR Question 40.102 and NUREG-0519, they concluded that the licensee s position was incorrect.During the inspection, the licensee performed preliminary calculations using the electrical transient analysis program (ETAP) and voltages based on the degraded voltage relay settings. These calculations showed that the safety related motors would start and accelerate satisfactorily. Based on these preliminary calculations the team concluded that this finding did not represent an operability concern. On November 12, 2010, the licensee issued IR 01139601 to determine whether the block start, at a bus voltage of 3833V (minimum degraded voltage relay reset afforded by the degraded voltage protection scheme), is part of the LaSalle design basis. On December 15, 2010, engineering initiated action item IR 01139601-03 to perform a formal analysis at a switchyard voltage that results in a recovery voltage at the minimum degraded voltage relay reset of approximately 3833V, at the 4 kV buses and revise Calculation L-003364 accordingly.Concerning this finding, the licensee stated that the NRC previously reviewed License Amendment number 135/120 and the associated Safety Evaluation Report (SER) and concluded that the setpoint change for the undervoltage relay was acceptable. However, the team could not identify in the SER that the NRC specifically reviewed the licensee s motor block start analysis at the worst case bus voltage of 3833 Vac (minimum degraded voltage relay reset value).This issue is considered unresolved pending resolution of differences in interpretation between the NRC and the licensee of the original licensing basis concerning motor-block- starting analysis. (URI 05000373/2010006-05; 05000374/2010006-05, Non-Conservative Voltage Input for Motor Starting Calculations.)ge Input for Motor Starting Calculations.)

Discovered date

23:59:59, 31 March 2011 +

Docket

05000373 + and 05000374 +

Event date

23:59:59, 31 March 2011 +

Finding

05000373/FIN-2010006-05 + and 05000374/FIN-2010006-05 +

Finding integer

5 +

Finding type

URI +

Has query"Has query" is a predefined property that represents meta information (in form of a <a rel="nofollow" class="external text" href="https://www.semantic-mediawiki.org/wiki/Subobject">subobject</a>) about individual queries and is provided by <a rel="nofollow" class="external text" href="https://www.semantic-mediawiki.org/wiki/Help:Special_properties">Semantic MediaWiki</a>.

IR 05000373/2010006 +

Issue report

AR 01139601 +

L

L-003364 +

Licensing Basis Document

Updated Final Safety Analysis Report +

Modification date"Modification date" is a predefined property that corresponds to the date of the last modification of a subject and is provided by <a rel="nofollow" class="external text" href="https://www.semantic-mediawiki.org/wiki/Help:Special_properties">Semantic MediaWiki</a>.

00:41:19, 21 February 2018 +

NUREG

NUREG-0519, Safety Evaluation of Final in-plant Safety/Relief Valve Test Evaluation Rept Per SER (NUREG-0519).Design Adequate to Accommodate Loads Associated W/Activation of One or More Safety Relief Valves +

4kV +

2011Q1 +

23:59:59, 31 March 2011 +

Title

Fast Bus Transfer Analysis +

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